William s



(No Model.)

W. S. HUGHES.

SLIDE VALVE.

No. 254,323. Patented Feb. 28.1882. Fly.

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\ d I l j Vi a f 'WITNESSES INVBNTOR UNITED STATES PATENT OFFICE.

WILLIAM S. HUGHES, OF LONG ISLAND CITY, NEW YORK.

SLI DE-VALVE.

SPECIFICATION forming part of Letters Patent No. 254,323, dated February 28, 1882.

Application filed August 8,1881. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM S. HUGHES, of Long Island City, Queens county, New York, have invented a new and useful Improvement in Slide-Valves, of which the following is a specification.

The object of my invention is to balance the slide-valves of steam-engines, especially locomotive-engines, and to prevent wear and concussionwhen the engine is running without steam. The invention consists in volute springs combined with a slide-valve in a manner to cut oil a portion of the pressure and at the same time. allow automatic adjustment of the valve, also, in a relief-valve combined with the slide-valve for release of air compressed in the cylinder.

In the accompanying drawings, Figure l is a plan view of a slide-valve containing my im= provements. Fig. 2 is a cross-section of the valve and steam-chest on line m m, Fig. 1, and Fig. 3 is an elevation of one of the balancingsprings.

Similar letters of reference indicate corresponding parts.

A is the valve-seat, provided with ports, and B is the slide-valve, formed with an exhaustcavity, as usual. The valve B isformed at its upper side with two annular cavities,a, which contain coiled or volute springs b b, that bear on the under side of the cover 0 of the steamchest. The ends of springs b are filed down to insure true bearings and contact of the springs the entire circumference of the coils, and a wearing-plate of hard metal, d, is secured on the coverc to prevent rapid wear by the movement of the valve.

It will be seen that the springs are cylinders that out 011' the area of surface which they inclose from pressure of steam. They are proportioned to leave so much surface exposed to pressure as is necessary to hold the valve ti ghtly to its seat against any ordinary back-pressure. Thesprings also allow the valve to rise or rock when there is pressure caused by the engine running without steam. The pressure of steam in the chest acts to close the outer coils of the springs b tightly together, thereby preventing entrance of steam to the interior, and without interfering with the elasticity of the spring.

The springs are prevented from collapsing under extreme pressure by the portion of valve B inclosed by the springs.

If desired, there may be a cap placed over each spring to bear on plate d, instead of having the springs take against the plate.

The side flanges, ff, of valve B are slotted or perforated, and the slots are covered by strips 99, of metal, held in place by flexible arms h h at their ends, which arms are attached to the end flanges of the valve B. The strips g serve as valves that close the slots when pressed down by steam pressure and give way to pressure from beneath, so as to relieve the main valve from the air-pressure caused when the pistons are working without steam.

In place of the valves g there may be valves, as shown at i, fitted in the upper surface of the main valve in recessed seats that connect by ports, as shown in dotted lines, with the valve ne'ar the edges of the exhaust-cavity. In either tease the valve B is relieved, and the rapid vibration and wear that take place with locomotive-valves are prevented.

These improvements are especially adapted for the valves of locomotive-engines, and for use with the improved valve patented to me April 26, 1881; but they may be used to advantage with any slide-valve to prevent rapid and unequal wear.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- The relief-valvesg, in combination with slidevalve B, provided with apertured flanges f, substantially as shown and described.

WILLIAM STEWART HUGHES. Witnesses:

GEo. D. WALKER, EDGAR TATE. 

